It has been known in controlling fluid flow through a faucet heretofore to provide a valve cooperating with a stationary valve seat wherein the valve is adapted to abut the rim of the valve seat in the closed position and to be removed therefrom in the open position so that fluid is permitted free egress from an inlet pipe through the valve chamber containing the valve and valve seat and thence through the outlet pipe into a sink or other fixture.
In returning the valve to the closed position it has proven necessary, in order to assure a positive and continuous seal between the valve and valve seat, obviating leakage through the outlet pipe or conduit, to provide for and overcome misalignment resulting from variations in temperature, mechanical factors and the like that often occur, at least over a period of time, between the valve and valve seat as well as irregularities in the rim of the valve seat itself. This has been accomplished heretofore with varying degrees of success by a multiplicity of different means known generically as swivel valves.
In order to avoid or limit substantially the erosion of the valve surface and the valve seat in the abutting closed position it has proven efficacious to provide that the valve be attached to the valve stem in such a manner that when the valve stem is rotated to close the valve, the valve may upon reaching an effective sealing position in the valve seat, assume a stationary posture, although, as frequently occurs, the valve stem is further rotated to increase the pressure on the valve and the abutment between valve and valve seat.
A variety of swivel valves have also been proposed to effect this purpose. Generally they have resulted in a multiplicity of component parts requiring a carefully balanced and calibrated relationship, awkwardness and significant cost in manufacture and assembly; the use of resilient materials susceptible to fatigue or deterioration over limited periods of time; the substitution of substantial erosion at the point of engagement of the valve with the valve stem for that occurring otherwise at the abutting surfaces of the valve and valve seat; and indeed, in some instances, a reduction in the effectiveness of the fluid seal to decrease erosion by use of less effective sealing materials which have better wearing properties.
In the event, therefore, that a swivel valve could be devised that would permit ready and economic manufacture and assembly, a simple valve construction incorporating a limited number of parts or an integral element capable of accommodating readily for misalignment in relation to a stationary valve seat and independent rotation of the valve stem when the valve is in an abutting position with the valve seat, and that would, at the same time, be composed of a long wearing material or materials that would assure an effective fluid seal and eliminate erosion substantially between valve and valve seat and minimal friction between valve stem and valve, a significant advance in the state of the art would be attained.